1. Field of the Invention
This invention relates to intersections for crossing streets, roads or highways having three or four branch lanes and providing for flow traffic regardless of the number of streets and the traffic direction. More particularly this invention relates to intersections comprising a two-level interchange of the inside lanes with the possibility of selecting a lane according to a geographic destination before approaching the intersection.
2. Description of the Prior Art
In projecting and constructing intersections having three or four branch lanes two structures are known, the so-called trumpet and the clover leaf, both comprising two-level interchanges. The use of these known structures is not satisfactory for several reasons. Due to minimum radius turns, fast flow-traffic is not possible using a trumpet. Traffic making a turn must pass through a 270 degree curve having only a minimum radius. The number of entrance and exit lanes, hereinafter called points of conflict, require special attention.
Such known intersections require large areas. A clover leaf having four branch lanes must include a 270 degree curve with a small radius. The number of points of conflict in rapid succession is as large as the area occupied.